SAN ANTONIO, Texas — “Why Miss Jones, you’re beautiful!” Watch enough late-night movies and you’ll likely recognize this cliché line from some cheesy black-and-white Hollywood B-flick. This exclamation usually follows the scene where the demure secretary removes her glasses and shakes the bun out of her hair, revealing her true bombshell self.

The mid-cycle upgrades to the 2016 Infiniti Q50 sport sedan elicit the same effect; only in this case, the line would be something like, “Why Miss Infiniti, you’re fast.” It’s not the cosmetics — the car has always had an attractive quality to it — it’s what’s under the hood. The tried-and-true 328-horsepower, 3.7-litre V6 from last year’s model has been tossed, with a choice of three powerful and more fuel-efficient turbocharged engines raring to take its place. For those who prefer their sporty sedans muy caliente, the top version — the Q50 Red Sport 400 — comes with a 400-horsepower, 3.0-litre twin-turbo V6, transforming the suddenly sexier Q50, which first debuted in 2014 as a replacement for the highly regarded G35/G37 sedans.

2016 Infiniti Q50 Red Sport 400Brian Harper /
Driving

This new VR30 V6 is also available with a milder 300-horse rating, which is expected to be the volume engine in the Q50’s lineup (3.0t Premium and Sport). The entry-level Q50 2.0t comes with a new turbo 2.0-litre four-cylinder — developed in conjunction with Daimler — producing 208 horses. For those with a greener conscience, there’s the carryover 360-horsepower hybrid powertrain, which combines a 3.5-litre V6 with a 50-kW electric motor and a compact laminated lithium-ion battery.

All engines are matched to a seven-speed electronically controlled automatic transmission with manual shift mode and steering column-mounted magnesium paddle shifters. Intelligent all-wheel drive is standard across the lineup for Canada.

But we were in U.S.-spec, rear-wheel-drive Red Sport models. Still, grip was more than sufficient for the dry roads around San Antonio, which tended to be well paved, arrow straight and with little change in elevation. In other words, the Dynamic Digital Suspension and handling didn’t get much of a workout. Neither did the much-touted — as the world’s first digital steering system — Direct Active Steering (part of the available Technology Package). However, we did give the Red Sport’s big engine a workout on a few occasions, and the thrust back into the seat when 400 horsepower was unleashed was immensely satisfying. The engine’s 350 lb.-ft. of maximum torque come in at 1,600 rpm and do not let go until 5,200 rpm.

2016 Infiniti Q50 Red Sport 400Brian Harper /
Driving

Fortunately, the people at Infiniti set up slalom and handling courses to provide a taste of what the Red Sport 400 could do. I first sampled the car without DAS, one time in Standard mode and the next in Sport+. (Located via menus displayed in the centre console, the car’s Drive Mode Selector allows steering response to be selected from six available options: Personal, Standard, Snow, Eco, Sport and — new for 2016 — Sport+.) Next up was a car with DAS and, again, I made one run in Standard mode and one in Sport+. Bottom line: If you’re into banzai runs on tight, twisting roads, you want the more intimate feedback DAS provides — with Sport or Sport+ mode engaged.

That said, it’s not just a performance feature. The steering ratio and effort is actively adjusted according to vehicle speed and situation. In slower-speed situations, such as city driving or when parking, the system is tuned for easier manoeuvring. (Interestingly, Nissan considers DAS to be a building block for future semi-autonomous driving operation.)

2016 Infiniti Q50 Red Sport 400Brian Harper /
Driving

The Q50’s Personal steering mode allows for a high degree of fine-tuning. Drivers first select one of three core modes (Standard, Sport or Sport+) and then specify the preferred level of response (Default, Dynamic and Dynamic+). For a slower steering response and conventional feel, a combination of Standard mode and Default response would be selected. For the highest level of assistance, Sport+ mode with Dynamic+ response would be chosen — making best use of DAS technology.

While power and performance is the sexy part, Infiniti hasn’t forgotten to coddle its occupants with modern conveniences and luxury items appropriate for the Q50’s upscale nature. New for 2016 are several feature-rich packages, available on all engine options and including auto-dimming power exterior mirrors with memory, heated steering wheel and front seats, power-adjustable steering wheel with memory and easy entry functions, Infiniti InTouch with navigation, navigation-synchronized adaptive shift control, SiriusXM Traffic, voice recognition and more. Models with the 3.0-litre V6 can add remote engine start.

2016 Infiniti Q50 Red Sport 400Brian Harper /
Driving

Since the debut of the G35 some 14 years ago, Infiniti has had a first-rate and well-balanced — if sometimes under-appreciated — sport sedan as a counterpoint against the established German marques. Not only does the revamped Q50 continue this tradition, it seriously ups the ante with the Red Sport 400, giving motor heads a new model to consider.

Infiniti Canada has yet to announce pricing on the Q50, which goes on sale in Canada in early spring. A reasonable expectation for the fun and fierce Red Sport 400 would be somewhere in the low-to-mid-$50K range.